Heavy oil conversion

ABSTRACT

A method of converting heavy oil into one or more valuable products comprises hydroconverting heavy oil, recovering an effluent stream from the hydroconverting, and deep catalytic cracking the effluent stream. The hydroconverting comprises reacting a slurry comprising unsupported fine catalyst in heavy oil. The effluent stream comprises unsupported fine catalyst in unconverted heavy oil. The deep catalytic cracking converts unconverted heavy oil into one or more light oil products.

BACKGROUND

As light oil reserves are gradually being depleted and the costs ofdevelopment (e.g., lifting, mining, and extraction) of heavy oilresources have decreased, a need has arisen to develop novel upgradingtechnologies to convert heavy oils and bitumens into lighter products.The “bottom of the barrel”, or high boiling range material (i.e., vacuumresidue) from crude oil, is difficult to convert into lighter productsvia conventional processes. Thus, what is needed are new technologiesthat achieve conversion of vacuum residue, which would offer significantpromise in resolving the problems associated with the disposition oflarge amounts of vacuum residue.

SUMMARY

Provided is a method of converting heavy oil into one or more valuableproducts. The method comprises hydroconverting heavy oil, recovering aneffluent stream from the hydroconverting, and deep catalytic crackingthe effluent stream. The hydroconverting comprises reacting a slurrycomprising unsupported fine catalyst in heavy oil. The effluent streamcomprises unsupported fine catalyst in unconverted heavy oil. The deepcatalytic cracking converts unconverted heavy oil into one or more lightoil products.

DETAILED DESCRIPTION

As used herein, “heavy oil” refers to an oil characterized by lowhydrogen to carbon ratios and high carbon residues, asphaltenes,nitrogen, sulfur and metal contents. Examples include atmospheric gasoils, vacuum gas oils, deasphalted oils, olefins, oils derived from tarsands or bitumen, oils derived from coal, heavy crude oils, syntheticoils from Fischer-Tropsch processes, and oils derived from recycled oilwastes and polymers.

The presently claimed method of converting heavy oil into one or morevaluable products comprises hydroconverting heavy oil, recovering aneffluent stream from the hydroconverting, and deep catalytic crackingthe effluent stream. The hydroconverting comprises reacting a slurrycomprising unsupported fine catalyst in heavy oil. The effluent streamcomprises unsupported fine catalyst in unconverted heavy oil. The deepcatalytic cracking converts unconverted heavy oil into one or more lightoil products.

As used herein, the phrases “light oil” and “light oil products” referto hydrocarbons or hydrocarbon mixtures (e.g., products of heavy oilupgrading) which boil below 700° F. (i.e., which have boiling rangesbelow that of a lubricant). For example, U.S. Pat. No. 6,841,062explains that the term “light gas oil” (LGO) can to be taken as areference to hydrocarbons or hydrocarbon mixtures which can be isolatedas distillate streams obtained during the conventional atmosphericdistillation of a refinery stream, a petroleum stream or a crude oilstream.

Catalyst Slurry

The presently described method utilizes catalysts in the conversion (inparticular, hydroconversion) of heavy oil (i.e., reaction of a slurrycomprising unsupported fine catalyst in heavy oil) into one or morelight oil products. In an embodiment, the catalysts are composedpredominantly of compounds such as a Group VI and/or Group VIII metalcompound sulfide, for example, molybdenum sulfide (MoS₂) and nickelsulfide (NiS), as described in U.S. Pat. No. 5,484,755 and U.S. PatentApplication Publication Nos. 2006/0054534 A1, 2006/0054535 A1,2006/0058174 A1, and 2006/0058175 A1, the contents of which are herebyincorporated by reference in their entireties. The highly active,unsupported catalysts typically exhibit particle size distributions inthe range of about 1-8 microns, with some smaller and larger particlesexisting on either end of the range. In particular, the catalystparticles can have a size distribution in the range of about 0.2-20microns, and a mean particle size of about 4-5 micron, with the modebeing about 6-7 micron.

Heavy Oil Upgrading

Suitable feeds to a process for upgrading heavy oils using the slurrycatalyst composition, include, for example, atmospheric residuum, vacuumresiduum, tar from a solvent deasphlating unit, atmospheric gas oils,vacuum gas oils, deasphalted oils, olefins, oils derived from tar sandsor bitumen, oils derived from coal, heavy crude oils, synthetic oilsfrom Fischer-Tropsch processes, and oils derived from recycled oilwastes and polymers. The feed is supplied to a reactor, wherein the feedis reacted with the catalyst slurry described in further detail belowand hydrogen. In an embodiment, the reactor is a liquid recirculatingreactor, although other types of upflow reactors may be employed. Thecatalyst slurry can be useful for, but not limited to, hydrogenationupgrading processes such as thermal hydrocracking, hydrotreating,hydrodesulphurization, hydrodenitrification, and hydrodemetalization.

The temperature of the reaction zone generally ranges from about 300° F.to about 600° F., for example, from about 350° F. to about 500° F. orfrom about 350° F. to about 450° F. The pressure of the reaction zonegenerally ranges from about 100 psig to about 3000 psig, for example,from about 200 psig to about 1000 psig or from about 300 psig to about500 psig. The hydrogen flow to the reaction zone generally ranges fromabout 300 SCFB to about 2000 SCFB, for example, from about 300 SCFB toabout 1000 SCFB or from about 300 SCFB to about 500 SCFB. The reactiontime in the reaction zone ranges from about 10 minutes to 5 hours, forexample, from 30 minutes to 3 hours or from about 1 hour to 1.5 hours.The resultant slurry mixture is the active catalyst composition inadmixture with the hydrocarbon oil. The heavy oil upgrading can compriseconditions, for example, as described in U.S. Patent ApplicationPublication Nos. 2006/0054534 A1, 2006/0054535 A1, 2007/0138055 A1, and2007/0138057 A1, the contents of which are hereby incorporated byreference in their entireties.

Processing of an effluent stream containing unsupported catalyst inunconverted feed is described herein. The effluent stream containingunsupported catalyst is primarily made-up of finely divided unsupportedslurry catalyst, carbon fines, and metal fines in unconverted residhydrocarbon oil. The effluent stream can comprise less than about 25volume %, for example, less than about 10 volume % or less than about 5volume %, of the feed to the heavy oil upgrading.

Processing of the effluent stream containing unconverted feed allows forgreater conversion of the feed (e.g., heavy oils, vacuum residue,bitumen, etc.) into lighter products. In particular, the deep catalyticcracking converts into lighter products unconverted material in thefeed, which otherwise would remain unconverted. Additionally, the deepcatalytic cracking utilizes active catalyst in the effluent stream,rather than requiring separation of the active catalyst from theeffluent stream or recycle of the active catalyst in the effluent streamto the heavy oil upgrading. Further, as the effluent stream to the deepcatalytic cracking comprises less than about 25 volume %, for example,less than about 10 volume % or less than about 5 volume %, of the feedto the heavy oil upgrading, the deep catalyst cracking reactor can bemuch smaller than the heavy oil upgrading reactor.

Deep Catalytic Cracking

As described above with regard to the heavy oil upgrading, the deepcatalytic cracking reactor can be a liquid recirculating reactor,although other types of upflow reactors may be employed. Similar to theheavy oil upgrading, the deep catalytic cracking can comprise, forexample, hydrogenation upgrading processes such as thermalhydrocracking, hydrotreating, hydrodesulphurization,hydrodenitrification, and hydrodemetalization.

According to the presently claimed method, the finely dividedunsupported slurry catalyst needs to still be active for hydrogenaddition. Similar to the heavy oil upgrading described above, thetemperature of the deep catalytic cracking zone generally ranges fromabout 300° F. to about 600° F., for example, from about 350° F. to about500° F. or from about 350° F. to about 450° F.; the pressure of the deepcatalytic cracking zone generally ranges from about 100 psig to about3000 psig, for example, from about 200 psig to about 1000 psig or fromabout 300 psig to about 500 psig; the hydrogen flow to the deepcatalytic cracking zone generally ranges from about 300 SCFB to about2000 SCFB, for example, from about 300 SCFB to about 1000 SCFB or fromabout 300 SCFB to about 500 SCFB; and the reaction time in the deepcatalytic cracking zone ranges from about 10 minutes to 5 hours, forexample, from 30 minutes to 3 hours or from about 1 hour to 1.5 hours.The deep catalytic cracking can comprise conditions, for example, asdescribed in U.S. Patent Application Publication Nos. 2006/0054534 A1,2006/0054535 A1, 2007/0138055 A1, and 2007/0138057 A1, the contents ofwhich are hereby incorporated by reference in their entireties.

The system could be operated as a continuous system or a batch system byintegrating the deoiling process with the heavy oil upgrading reactor.In particular, the effluent from the heavy oil upgrading reactor can besent directly to one of at least two batch reactors for collecting andthen deep cracking for a continuous flow system. The system pressuredoes not change. After deep cracking, the slurry can be sent to anotherlow pressure vessel for drying, and the light oil formed can be mixedwith all other light oils, eliminating the need for another distillationsystem for the deoiling process. The unit can be depressurized and thecatalyst dried in the same reactor.

Effluent streams from the upgrading reactor and deep catalytic crackingreactor, following downstream processing, such as, for example,separation(s), can include one or more valuable light oil products aswell as a stream containing unsupported catalyst in unconverted feed.Such separations can comprise methods described in U.S. application Ser.Nos. ______ (T-6553) and ______ (T-6554), the contents of which arehereby incorporated by reference in their entireties, filed concurrentlyherewith.

Many modifications of the exemplary embodiments disclosed herein willreadily occur to those of skill in the art. Accordingly, the presentdisclosure is to be construed as including all structure and methodsthat fall within the scope of the appended claims.

1. A method of converting heavy oil into one or more valuable products,the method comprising: hydroconverting heavy oil, wherein thehydroconverting comprises reacting a slurry comprising unsupported finecatalyst in heavy oil; recovering an effluent stream from thehydroconverting, wherein the effluent stream comprises unsupported finecatalyst in unconverted heavy oil; and deep catalytic cracking theeffluent stream, wherein the deep catalytic cracking convertsunconverted heavy oil into one or more light oil products.
 2. The methodof claim 1, wherein the catalyst comprises particles having a sizedistribution in the range of about 0.2 to about 20 microns and a meanparticle size in the range of about 4 to about 5 micron, wherein a modeof the size distribution is in the range of about 6 to about 7 micron.3. The method of claim 1, wherein the catalyst comprises a Group VIand/or Group VIII metal compound sulfide.
 4. The method of claim 1,wherein at least a portion of the slurry comprising unsupported finecatalyst in heavy oil comprises a product of an ebulating bed reactor.5. The method of claim 1, wherein the deep catalytic cracking isconducted at a temperature of about 300° F. to about 600° F.
 6. Themethod of claim 1, wherein the deep catalytic cracking is conducted at aresidence time of about 10 minutes to 5 hours.
 7. The method of claim 1,wherein the deep catalytic cracking is conducted at a pressure of about100 psig to about 3000 psig.
 8. The method of claim 1, wherein the deepcatalytic cracking comprises hydrogen flow of about 300 SCFB to about2000 SCFB.
 9. The method of claim 1, wherein the deep catalytic crackingcomprises a batch system.
 10. The method of claim 1, wherein the deepcatalytic cracking comprises a continuous system.
 11. The method ofclaim 1, further comprising separating unsupported fine catalyst fromthe one or more light oil products.
 12. The method of claim 1, whereinthe separating comprises drying the catalyst.
 13. The method of claim12, wherein the deep catalytic cracking is conducted in a reactor andthe drying is conducted in the same reactor as the deep catalyticcracking.
 14. The method of claim 12, further comprising depressurizingthe reactor after the deep catalytic cracking and prior to the drying.15. The method of claim 1, wherein the separating comprises sending theunsupported fine catalyst and the one or more light oil products to alow pressure vessel for drying.
 16. The method of claim 15, furthercomprising mixing the unsupported fine catalyst and the one or morelight oil products with one or more additional light oil products priorto drying.
 17. The method of claim 1, where the effluent streamcomprises less than about 25 volume % of the slurry comprisingunsupported fine catalyst in heavy oil.
 18. The method of claim 1, wherethe effluent stream comprises less than about 10 volume % of the slurrycomprising unsupported fine catalyst in heavy oil.
 19. The method ofclaim 1, where the effluent stream comprises less than about 5 volume %of the slurry comprising unsupported fine catalyst in heavy oil.